Rounding : Magnetic Headings

[lnuss]

(To be honest, I don't think I ever even saw a decimal heading myself.)

 

Nor have I, in all my years in real world aircraft --never even heard of such a presentation in an aircraft. Besides, you're doing well to actually fly accurately within one degree. Unless you have an extreme long range aircraft and trip (thousands of miles) and hold an absolutely constant heading (tough, even with autopilot and excellent electronics), through all the magvar , wind and pressure (among other things) changes enroute, you'll never know the difference within a couple of tenths (and more) of a degree anyway.

[flyer8]

To think this out, I would 'overdo it' in an imaginary example.

lets say you have rw-1, 10 degrees, and it is actually 10.4 degrees.

Overdoing, in imaginary example, lets say its Rw-1, 10 degrees, but the actual heading is 20 degrees.

what would you do.

 

fly to the airport at heading 10 degrees, then 2 or three miles out or so you would have to swerve strongly left, fly for a bit, and then swerve strongly right to get in line with the runway.

 

If the difference is just a two tenths of a degree, as in the first example, the swerve is of course much less.

 

That example at the top of this post:

lets say you have rw-1, 10 degrees, and it is actually 10.4 degrees.

if my HSI indicated only full degrees I would fly towards the airport at 10 degrees. (10.4 is closest to 10)

then swerve slightly left a few miles out,

and swerve right again.

 

By that time the runway would be in view. Landing is visual.

I would just have this in my mind to be able to better anticipate.

 

I would round anything below 0.5 down to 0

0.5 and above to 1

(the nearest whole number basically.)

 

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In an ILS landing situation there is no need for all of this. The localiser puts you on the correct heading anyway. decimals and all.

 

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(To be honest, I don't think I ever even saw a decimal heading myself.)

 

Me neither and I totally agree, haven't used it in the sim myself. As I fly mostly steam, it could be considered irrelevant, at least for me. As I was saying to the String Bean, I have a bunch of data which is crying for a format. Its a decimal list of 57, 657 runways and the default GPS shows that its rounding the data. Just want to know which rounding its using so I can apply it to the dataset.

 

The swerve theory sounds like a real flight I took into CYVR. The pilot was banking a 737 at about 35 degrees to lineup with the runway. I didn't have the wherewithal to ask him if all that turning lead to an ILS or if he was trying to hold the approach to the decimal place. But it was fun for me, a bit unnerving for some of the others.

 

It is interesting to find out what pilots overdo, don't want to push a bad position, I know that much. For me it's better to be a bit pedantic and prepared. Especially when working with an initial dataset, one that can be used more loosely downstream.

 

Well, thanks for the help and Best Regards three!

 

EDIT: 59,567 rows of runway data!

[flyer8]

Nor have I, in all my years in real world aircraft --never even heard of such a presentation in an aircraft. Besides, you're doing well to actually fly accurately within one degree. Unless you have an extreme long range aircraft and trip (thousands of miles) and hold an absolutely constant heading (tough, even with autopilot and excellent electronics), through all the magvar , wind and pressure (among other things) changes enroute, you'll never know the difference within a couple of tenths (and more) of a degree anyway.

 

Interesting, and something that I had hoped to read. I would never had thought anything other than an autopilot could hold a decimal heading.

 

With underlying data, engineers hold initial datasets to a more exact standard in hopes of mitigating the propagation of error downstream. Like the plus factors we would hold mission critical F5 or T-38 systems to in case there was a bit more turbulence than expected. Also known as advanced and hopefully, excellent avionics.

 

Flight Simulator knows none of this and contains varying standards, as it should. I'm investigating the rounding factors used by the simulation for the fun of it, but at the same time, was interested in what real pilots actually do and use.

 

Thanks for this...cool content!

[pschlute]

The pilot was banking a 737 at about 35 degrees to lineup with the runway. I didn't have the wherewithal to ask him if all that turning ....... was trying to hold the approach to the decimal place.

 

 

It wasn't !

[flyer8]

It wasn't !

 

Paul, that was my attempt at humor. Funny thing, that CYVR landing both actually happened and I had spoken to the pilot about it. He gave me this big grin when I was speaking to him, as if he's always on a leash but that rad approach into Vancouver was his moment of freedom.

 

It was fun as I could tell he was a great guy, must have been x-mil and missed the speed. Used to work with a bunch of them and what did they say in the movie Avitar, once a marine, always a marine. Fine by me as I fly the flag on my little Cessna as well.

 

By the way, thanks for all of the good advice in this post! Very helpfull...

 

Best Regards!

[PhantomTweak]

Wow! I bet a flag is pretty high-drag. :)

Used to work with a bunch of them and what did they say in the movie Avitar, once a marine, always a marine.

Very, very true. And once a Nasal Radiator, always a Nasal Radiator. My father was a Naval Flight Instructor in AT-6's a while back at Pensacola, and when he was flying for UAL he liked to have a little fun once n a while. Suprizingly, a DC-8 is a very agile aircraft.

As is a 737. We made one landing at Portland that any carrier qualed Aviator would be proud of :D Hot day, heavy load, little too much fuel, and he was going to make the taxiway 1/2 way down the runway no matter what. He planted that plane, hit the reversers, spoilers, brakes...and we made it. Barely. They had to use the ailerons to try and keep the plane upright during the turn. Fun times!

Have fun all, and keep 'er on course! To the last decimal point! ;)

Pat☺